DARIEN, Conn. -- Commuters and homeowners on the Stamford-Darien border beware: Traffic may get a lot worse when the state begins work to replace a bridge that carries Route 1 over the Noroton River.

The 50-foot bridge set for replacement was built in 1913 and rehabilitated in 1956. The bridge carries two lanes of Route 1 traffic in each direction, with an estimated daily usage by 10,600 vehicles, according to the state Department of Transportation.

The bridge is currently in fair condition but has been identified by the DOT's Bridge Safety and Evaluation Unit as "scour critical," meaning that the river is eroding soil near the bridge and could risk undermining the foundation. Some deterioration and cracks have appeared in the concrete, and some of the reinforcing steel and steel beams show signs of corrosion, according to the DOT.

The DOT has proposed that construction of the replacement bridge begin in 2016. The recommended replacement will consist of a new steel multi-girder superstructure with a concrete deck and concrete abutments. It will be raised 2.5 feet to meet minimum hydraulic opening requirements.

When completed, the bridge will be 62 feet wide with four travel lanes, a left-turn only lane and two 4-foot shoulders. There will be a 6-foot wide sidewalk on the south side and a sidewalk on the north side of varying widths.

During construction of the new bridge, two lanes of traffic will be diverted to a temporary bridge just north of the current bridge's location, with an additional lane of traffic on the existing bridge. The intersection of Brookside Drive and Route 1 will be closed, and Brookside Drive traffic will be detoured to Anthony Lane and Hillside Avenue.

The bridge replacement is included in the DOT's 2014-18 capital plan. The project is expected to impact 5,000 square feet of inland wetlands, and will require permits from the state Department of Energy and Environmental Protection, as well as the Army Corps of Engineers.

The project is expect to cost $7 million to $8 million. About 80 percent of the project will be funded through the federal government, with the rest coming from the state. The DOT expects construction to begin in the summer of 2016, with an anticipated construction time of 24 months. The DOT said the schedule is preliminary and subject to change.